Aubagio is less effective than rival pills but has milder side effects and analysts say it could be popular among newly diagnosed patients or those who want to switch from interferons, injectable drugs that are commonly used to treat the chronic disease.

Genzyme also said it is making progress toward refiling Lemtrada in the United States, after the Food and Drug Administration asked the company to change the presentation of its application to clarify the data.

"We are on track to satisfy the questions of navigability from the FDA," said Michael Panzara, therapeutic area head for multiple sclerosis and immune diseases at Genzyme. "We are also having interactions with regulators around the world which are very favourable."